Field of the Invention
The present invention relates to a displacement detection apparatus that detects a displacement of a surface to be measured, using the light emitted from a light source.
Description of the Related Art
Conventionally, as the apparatus that contactlessly measures a displacement of a surface to be measured, a displacement detection apparatus using light has been widely used. Various types of schemes are available for the displacement detection apparatus. A specific configuration of the displacement detection apparatus will be described later in the embodiments. In any of the schemes, the displacement detection apparatus is configured to guide the light from a light source to a displacement detector through an optical fiber. Then, the displacement detection apparatus varies the phase of the light from the light source based on a displacement of the surface to be measured and detects a change state of the phase of the light, thereby detecting the amount of displacement of the surface to be measured.